C#: SerializableAttribute could not be found

Question

I am trying to use the [Serializable] attribute in a C# class library project (latest .NET version), but it is not recognised.

As far as I could search, Serializable it something that belongs in ~~System.Runtime.Serialization~~ System, but I have used it and it still doesn't work.

I am using it in other projects (Unity), but it doesn't work here. Any ideas?

using System;
using System.Runtime;
using System.Xml.Serialization;
using System.Runtime.Serialization;
using System.Collections.Generic;

namespace Model{
    [Serializable]
    public struct GameSettings{
        public int Players;
    }
}

Thank you in advance

Edit: format Edit2: screenshot of the error

What is your environment? .Net 4.5? .Net core? Unity3d? Something else? — dbc, Jun 11 '17 at 21:03
@dbc I am using the latest .NET version for a .NETCoreApp v1.1 — Sindorej, Jun 11 '17 at 22:27
@dbc The [Serializable] attribute does work in Unity, but that is a standalone class library (as I mentioned above) — Sindorej, Jun 11 '17 at 22:27
Have you disabled the core libraries in your project (e.g. https://stackoverflow.com/a/35902373/34092 or https://stackoverflow.com/a/11560352/34092 )? — mjwills, Jun 11 '17 at 22:37
Define 'doesn't work'? Do you mean 'it doesn't compile' or something else? If something else, talk us through what that looks like. — mjwills, Jun 11 '17 at 22:38
This is the error I am getting. [link](http://prntscr.com/finarm) I'm checking out the linked questions now — Sindorej, Jun 11 '17 at 22:41
@mjwills I checked the links you have provided and no; I have not done anything to remove mscorelib from the references — Sindorej, Jun 11 '17 at 22:44
Possible duplicate of [What is the equivalent of \[Serializable\] in .NET Core ? (Conversion Projects)](https://stackoverflow.com/questions/39199049/what-is-the-equivalent-of-serializable-in-net-core-conversion-projects) — mjwills, Jun 11 '17 at 22:51

Christian Gollhardt · Answer 1 · 2017-06-11T21:39:27.127

3

This attribute lives in System, not in System.Runtime.Serialization:

namespace System
{
  /// <summary>Indicates that a class can be serialized. This class cannot be inherited.</summary>
  [AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct | AttributeTargets.Enum | AttributeTargets.Delegate, Inherited = false)]
  [ComVisible(true)]
  public sealed class SerializableAttribute : Attribute
  {
      //...
  }
}

Are you sure you have referenced mscorlib.dll? This question might be interessting for you.

edited Jun 11 '17 at 21:39

answered Jun 11 '17 at 21:17

Christian Gollhardt

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As you can see System is already being used. I did try to explicitly add mscorlib.dll in the dependencies but that created even more errors. – Sindorej Jun 11 '17 at 22:26
The answer from Christian seems correct for Unity. At least, it worked for me after freshly installing Unity 2018.3.8f1 and the corresponding VisualStudio package. – Erik Hermansen Mar 16 '19 at 21:08
Yeah, the question later changed into a .net core question. – Christian Gollhardt Mar 16 '19 at 21:14

score 3 · Accepted Answer · answered Jun 12 '17 at 15:13

https://apisof.net/catalog/System.SerializableAttribute shows that [Serializable] is defined in the System.Runtime.Serialization.Formatters package for .NET Core 1.0 and 1.1 and .NET Standard 1.6. It then moved to System.Runtime for .NET Core 2.0 and the netstandard monolith for .NET Standard 2.0.

If you just care about being able to compile shared code, you could try adding the package reference. But What is the equivalent of [Serializable] in .NET Core ? (Conversion Projects) has already answered that the binary serializer isn't in .NET Core 1.x (unsure about its 2.0 status... but since 2.0 is in preview you could always try it out).

C#: SerializableAttribute could not be found

2 Answers2